1. Field of the Invention
The present invention relates to a radiation detection element. In particular, the present invention relates to a radiation detection element having plural pixels that are disposed in a matrix in a rectangular detection region, that accumulate charges generated by irradiation of radiation, and that includes switching elements to read out the accumulated charges.
2. Description of the Related Art
Recently, radiographic imaging devices using a radiation detection element, have been put into practice employing a radiographic imaging element of a FPD (flat panel detector), or the like. Such radiographic imaging elements have an X-ray sensitive layer disposed on a TFT (Thin Film Transistor) active matrix substrate, and are able to directly convert X-ray information into digital data. Such FPDs have the merit that, in comparison to with previous imaging plates, images can be more immediately checked and video images can also be checked. Consequently the introduction of FPDs is proceeding rapidly. Various types are proposed for such radiographic imaging elements. There are, for example, direct-conversion-type radiographic imaging elements that convert radiation directly to charge in a semiconductor layer, and accumulate the charge. There are also indirect-conversion-type radiographic imaging elements that first convert radiation into light with a scintillator, such as CsI:Tl, GOS (Gd2O2S:Tb) or the like, then convert the converted light into charge in a semiconductor layer and accumulate the charge.
In the radiation detection element, plural scan lines and plural signal lines are disposed to intersect each other. In the radiation detection element, pixels are provided in a matrix at the intersection portion of the plural scan lines and the plural signal lines. The plural scan lines and the plural signal lines are connected to an external circuit (for example, an amplifier integrated circuit (IC) or a gate IC) at a peripheral portion of the radiation detection element.
Japanese Patent Application Laid-Open (JP-A) No. 2003-264273 discloses a technology that facilitates the connection of the scan lines and the signal lines with an external circuit at a peripheral portion of a radiation detection element. According to this technology, as shown in FIG. 6, scan lines 101′ and signal lines 3′ are disposed to be inclined at an angle of 30° to 60°, to a substrate including an approximately rectangular detection region 30′ for detecting the irradiated radiation. This technology increases the arrangement pitch of connecting portions of the scan lines 101′ and the signal signals 3′ with the external circuit for 1/sin θ times.
However, when the scan lines and the signal lines are disposed to be inclined using the technology disclosed in JP-A No. 2003-264273, the variation of the wiring load of the scan lines and the signal lines increases in a central portion and in an end portion. This is because the length or the number of connected pixels of the scan lines and the signal lines is different in the central portion and the end portion of the detection region. Accordingly, when the variation of the wiring load of the scan lines and the signal lines increases, image quality and driving capability in the detection region may be insufficient.